Description from the website: "Restwise takes the science of recovery out of the lab and puts it into your hands. Answer a brief series of research-based questions on the Restwise website every day, and the resulting Recovery Score will, for the first time ever, quantify your body's state of recovery."http://www.restwise.com/

The post is from a guy who did sub-9 in Kona and won a bunch of races this year, and he challenges a lot of conventional wisdom about training. (He did sub-9 with an average of 12 hours of training per week.) Anyway, here is what he said about RestWise:

"I started using Restwise (which I’d highly recommend to every athlete) to better quantify my recovery (chart from last 3 months below). If my recovery score was too low, I took a rest/easy day until the scores were up (80-100%)."